Martin Edward Murphy, commonly known by the pseudonym Martin Plaza, is an Australian singer-songwriter, musician and visual artist who is a founding member and vocalist and guitarist of the new wave band Mental As Anything. He has also worked with other bands and is an accomplished artist. Plaza also has a solo music career and had a No. 2 hit in Australia with his 1986 cover of the song "Concrete and Clay".

Mental As Anything are an Australian new wave and pop rock band that formed in Sydney in 1976. Its most popular line-up was Martin Plaza on vocals and guitar; Reg Mombassa on lead guitar and vocals; his brother Peter "Yoga Dog" O'Doherty on bass guitar and vocals; Wayne de Lisle on drums; and Andrew "Greedy" Smith on vocals, keyboards and harmonica. Their original hit songs were generated by Mombassa, O'Doherty, Plaza and Smith, either individually or collectively; they also hit the Australian charts with covers of songs by Roy Orbison, Elvis Presley, and Chuck Berry.